Duff 1982.

Methods	Design: randomised double‐blinded No. eligible: not stated No. randomised: "91 enrolled" No. analysed: 91 Drop‐outs/withdrawals: none reported Years of recruitment: 1979 to 1981 Setting: army medical centre, USA
Participants	Inclusion criteria: all women undergoing abdominal hysterectomy for benign disease Exclusion criteria: antibiotics received in past 4 weeks, penicillin or cephalosporin allergy Age: 39 to 40 years Type of hysterectomy: abdominal
Interventions	Treatment: 1 gram cefoxitin (second‐generation cephalosporin) Control: placebo Route: IV Single/multiple doses: multiple Timing of doses: 30 minutes preoperatively and 4 hours later
Outcomes	Postoperative infection, early Abdomnal wound infection Urinary tract infection Pelvic infection Need for therapeutic antibiotics Adverse effects (narrative data only) Length of hospital stay
Funding	Not stated
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomly allocated" ‐ no details given
Allocation concealment (selection bias)	Low risk	"Only the hospital pharmacist routinely had access to the protocol code before completion of the study"
Blinding (performance bias and detection bias) All outcomes	Unclear risk	"Both the patient and the attending physician were blinded as to the medication assignment"; no additional details provided with respect to outcome assessment
Incomplete outcome data (attrition bias) All outcomes	Low risk	It appears that all participants randomised were analysed
Selective reporting (reporting bias)	Low risk	Outcome data available on all prespecified outcomes
Other bias	Low risk	Baseline demographic characteristics similar between treatment groups